The present invention relates to a method of disinfecting one or more surfaces and/or sterilizing air, and an apparatus for use in said method.
In industrial kitchens, in air conditioning systems and in the hospital sector it is known that frequent cleaning and disinfection is a requirement. However, conventional cleaning with soap, water and disinfecting detergent chemicals is often not sufficient. Alternative cleaning agents have to be applied, and particularly ozone (O3) has proven to be successful.
Ozone has long been recognized as a useful gas/chemical commodity valued particularly for its outstanding oxidative activity. Because of this activity it finds wide application in disinfection processes. In fact, it kills bacteria/vira/mould more rapidly than chlorine, it decomposes organic molecules, and removes coloration in aqueous systems. Ozonation removes cyanides, phenols, iron, maganese, and detergents. It controls biofilm formation in aqueous systems, yet maintains a high oxygen content in the system. Unlike chlorination, which leaves undesirable chlorinated organic residues in organic containing systems, ozonation leaves fewer potentially harmful residues. There is evidence that ozone also is capable of destroying viruses. It is used for sterilization in the brewing industry and for odor control in sewage treatment and manufacturing.
Thus, ozone has widespread application in many diverse activities, and its use would undoubtedly expand if its cost of production could be reduced. In addition, since ozone is explosive when concentrated as either a gas or liquid, or when dissolved into solvents, its transportation is potentially hazardous. Therefore, it is generally manufactured on the site where it is used. However, the cost of generating equipment, and poor energy efficiency of production has deterred its use in many applications and in many locations.
On a commercial basis, ozone is often produced by the silent electric discharge process, otherwise known as corona discharge, wherein air or oxygen is passed through an intense, high frequency alternating current electric field.
Another way of producing ozone is by use of UV radiation. UV radiation is characterised by waves, with a wavelength in the area of 10 nm to 380 nm. UV radiation is typically divided into three different subgroups UV-A, UV-B and UV-C, with wavelengths of approximately 320-380 nm, 280-320 nm and 100-280 nm, respectively. UV-C radiation is known to destroy most organic molecules and is e.g. used in the hospital sector for sterilising medical equipment. However, at wavelengths of 100 nm to 240 nm, UV radiation is known to produce ozone from oxygen (O2) for example contained in air.O2+photon→2OO+O3→O3 
However, even though generation of ozone using corona discharge is extremely expensive it is conventionally considered as the only possible way of generating sufficient ozone for disinfecting purposes.
Due to it's strong oxidising effect, ozone is however also hazardous to humans even at low concentrations, as it causes injury on the respiratory system. Today's methods of disinfecting by use of ozone thus continuously have to be improved in regards to safety.
Attempts have been made to develop a successful and safe disinfection. US2006/0263276A1 relates to a mobile ozone generating apparatus for disinfecting an isolated room. The apparatus comprises among others more openings, at least one UV lamp and a ventilator. With use of a remote controller and a timer the apparatus can be turned on and off from a distance. The ventilator moves air from the isolated room into the apparatus and close to the at least one UV lamp. The air is thus irradiated by the UV lamp resulting in the production of ozone. The air now containing a larger concentration of ozone is then released to the room. It is stated that the concentration of ozone can be increased by increasing the number of UV lamps or alternatively the flow rate of air through the apparatus. The primary target of using the apparatus is to disinfect the air in the room. However, it is stated that the apparatus is also used for disinfect surfaces in the room at higher ozone concentrations. Finally, the apparatus can be equipped with more outlets so that more rooms can be disinfected simultaneously.
WO2006/095199A1 relates to an apparatus for removing unpleasant odour and impurities from air and for preventing impurities in accumulating on surfaces. The apparatus consists of two sections, a first section through which air is flown and added ozone, and a second section through which the air subsequently flows, and where excess ozone is converted into oxygen. The two sections of the apparatus are placed with a distance to each other for example in the tubes of a ventilation system, but can also be a mobile separate apparatus having it's own tube system. The ozone can be produced and added to the air in the first section by irradiating the air with UV radiation from one or more UV lamps with a wavelength of preferably 185 nm. Alternatively, the ozone can be produced from air outside the tube system and subsequently added to the air inside the tube system.
Known apparatuses and methods for disinfecting surfaces and/or sterilizing air do thus not present a simple and effective safety system to minimise health risks for persons using the apparatuses. Furthermore, the known apparatuses are not simple, economical and convenient to use. Additionally, they are not capable of producing the desired high concentration of ozone from ambient air capable of sterilising all the required surfaces.